Architectural Debt

Architectural Debt
Architectural debt is the concept that adding complexity to an already complex system will generate debts
(technical, commercial, process, etc) that will need to be ‘unwound’ at a future date.
This is illustrated below:
Integration complexity (or ‘coupling’) increases as architectural integrity decreases. Simply put when issues are
fixed tactically – with rigorous impact analysis – the ‘string gets longer and harder to unravel.’ These types of
changes tend not to update business processes or similar documentation making the understanding of that
change hard to understand in the future.
This situation increases the speed that architectural debt is accumulated because it is extremely difficult to
consider any solution other than a fix that builds on previous tactical changes. The understanding of the original
solution – both in terms of what is being solved and how it is being solved is lost.
Eventually this becomes unsustainable. Either the debt has to be unwound through an expensive and time
consuming experience of reverse-engineering back to the original solution, or – as is more likely – the solution is
replaced by an entirely new approach starting from scratch.
Architectural debt is generated to IT systems, data models and management, business processes and
organisational design. It is mitigated by having strong governance and architecture functions within an
organisation, and senior management buy in to properly understanding the impact of change, before embarking
on it.